Due to the extension of the Internet and evolvement of communication technology, people are more and more often sharing information within virtual communities using services provided by and/or via the Internet. A virtual community is a place where the members of the community exchange messages with each other, said messages being text messages, voice messages, video messages, different types of multimedia messages, etc. Some examples of a virtual community (hereinafter called a community) include “buddy list” type of lists of friends in instant messaging, address books in email applications or chat room membership lists. There are several ways to form a community when the Internet, or any other software based mechanism requiring user registration, is used. However, there is no mechanism to form a community without each member's specific registration to join the community, and using identifiers relating to units identifiable by a communication system.